fix undocumented unexpected LokiInitPaths

diff --git a/tools/quake3/q3map2/path_init.c b/tools/quake3/q3map2/path_init.c
index 16758c6db40fecf7de6df655aadc03b8f8f47e4b..be28c20345c46741fee9dea7c472039260a1a25c 100644 (file)
--- a/tools/quake3/q3map2/path_init.c
+++ b/tools/quake3/q3map2/path_init.c
@@ -122,7 +122,6 @@ void LokiInitPaths( char *argv0 ){
        strcpy( installPath, "../" );
        #else
        char temp[ MAX_OS_PATH ];
-       char last0[ 2 ];
        char        *path;
        char        *last;
        qboolean found;
@@ -136,6 +135,25 @@ void LokiInitPaths( char *argv0 ){
                argv0 = strrchr( argv0, '/' ) + 1;
        }
        else if ( path ) {
+
+               /*
+                  This code has a special behavior when q3map2 is a symbolic link.
+
+                  For each dir in ${PATH} (example: "/usr/bin", "/usr/local/bin" if ${PATH} == "/usr/bin:/usr/local/bin"),
+                  it looks for "${dir}/q3map2" (file exists and is executable),
+                  then it uses "dirname(realpath("${dir}/q3map2"))/../" as installPath.
+
+                  So, if "/usr/bin/q3map2" is a symbolic link to "/opt/radiant/tools/q3map2",
+                  it will find the installPath "/usr/share/radiant/",
+                  so q3map2 will look for "/opt/radiant/baseq3" to find paks.
+
+                  More precisely, it looks for "${dir}/${argv[0]}",
+                  so if "/usr/bin/q3map2" is a symbolic link to "/opt/radiant/tools/q3map2",
+                  and if "/opt/radiant/tools/q3ma2" is a symbolic link to "/opt/radiant/tools/q3map2.x86_64",
+                  it will use "dirname("/opt/radiant/tools/q3map2.x86_64")/../" as path,
+                  so it will use "/opt/radiant/" as installPath, which will be expanded later to "/opt/radiant/baseq3" to find paks.
+               */
+
                found = qfalse;
                last = path;
 
@@ -157,17 +175,20 @@ void LokiInitPaths( char *argv0 ){
                                path++;
                        }
 
+
                        /* concatenate */
                        if ( last > ( path + 1 ) ) {
-                               Q_strncat( temp, sizeof( temp ), path, ( last - path ) );
+                               // +1 hack: Q_strncat calls Q_strncpyz that expects a len including '\0'
+                               // so that extraneous char will be rewritten by '\0', so it's ok.
+                               // Also, in this case this extraneous char is always ':' or '\0', so it's ok.
+                               Q_strncat( temp, sizeof( temp ), path, ( last - path + 1) );
                                Q_strcat( temp, sizeof( temp ), "/" );
                        }
-                       Q_strcat( temp, sizeof( temp ), "./" );
                        Q_strcat( temp, sizeof( temp ), argv0 );
 
                        /* verify the path */
                        if ( access( temp, X_OK ) == 0 ) {
-                               found++;
+                               found = qtrue;
                        }
                        path = last + 1;
                }
@@ -175,9 +196,12 @@ void LokiInitPaths( char *argv0 ){
 
        /* flake */
        if ( realpath( temp, installPath ) ) {
-               /* q3map is in "tools/" */
+               /*
+                  if "q3map2" is "/opt/radiant/tools/q3map2",
+                  installPath is "/opt/radiant"
+               */
+               *( strrchr( installPath, '/' ) ) = '\0';
                *( strrchr( installPath, '/' ) ) = '\0';
-               *( strrchr( installPath, '/' ) + 1 ) = '\0';
        }
        #endif
 }